That is tough. I think that you're going to see the WR duo of Boldin/Fitz have their #'s slip a little bit as a result of the QB switch. Leinhart is going to be a good QB, but right now his OLine is putrid and I think they may rely more on the EDGE in order to take pressure off of Leinhart.
Besides, your team is young, and there is an awful lot of potential within your WR core.
Evans has started to come around and it is only a matter of time before he gets into the endzone.
Jennings is starting to get more looks in GB than the #1 guy Driver.
Cotchery is proving to be a valuable #3 WR.
Edwards is becoming the STUD that he was drafted to be and has become the favorite target of QB Frye.
I think you may want to target someone who doesn't have as many question marks about the offense as Fitz...Rookie QB, stud RB that demands touches, another STUD WR playing opposite him, and a horrible oline.
Hope this helped!